Development of a fluoride chronic effects benchmark for aquatic life in freshwater.

Canada has an interim water-quality guideline for fluoride for protection of freshwater aquatic life that dates from 2002, and 1 Canadian province has a different interim water-quality guideline for fluoride that dates to 1995. The United States does not have a national benchmark for fluoride in freshwater, and only 1 US state has such a benchmark. There are no other national or regional benchmarks for fluoride chronic toxicity in freshwater.

In vitro biotransformation rates in fish liver S9: effect of dosing techniques.

In vitro biotransformation assays are currently being explored to improve estimates of bioconcentration factors of potentially bioaccumulative organic chemicals in fish. The present study compares thin-film and solvent-delivery dosing techniques as well as single versus multiple chemical dosing for measuring biotransformation rates of selected polycyclic aromatic hydrocarbons in rainbow trout (Oncorhynchus mykiss) liver S9. The findings show that biotransformation rates of very hydrophobic substances can be accurately measured in thin-film sorbent-dosing assays from concentration-time profiles in the incubation medium but not from those in the sorbent phase because of low chemical film-to-incubation-medium mass-transfer rates at the incubation temperature of 13.